How do you get it to do that, Chris?
C
It's got a setting in location services that keeps an eye out on frequent places you go to regularly. If you let it.
The notification screen has a day summary, and if you open it near to a time when you usually travel, it'll check the traffic on your route and estimate how long it will take, so usually from around 4.30 if I'm at the office it will tell me something like "it will take you 16 minutes to drive home" on the pull-down notification thingy, as well as a weather summary, my next appointment and some information about my calendar for tomorrow.
My favourite is when there's an early start in the calendar, it'll tell you to get an early night as it looks like a busy day ahead. Thought that was hilarious the first time it happened.
You can block it from doing this if you're paranoid about it keeping tabs on you by turning it off in location settings.